Arginine bicarbonate has use in various industrial applications, including use in personal care compositions, such as oral care compositions. For example, U.S. Pat. No. 6,524,558 describes the use of arginine bicarbonate and calcium carbonate for preventing or treating dental hypersensitivity. As the industrial requirements for arginine bicarbonate increase, so will the need for improved processes and methods for its manufacture.
PCT published application WO2009/100267, the contents of which are incorporated herein in their entirety as if set forth in full, describes methods of production of arginine bicarbonate.
Arginine bicarbonate may be produced by bubbling carbon dioxide gas through a saturated arginine aqueous solution at room temperature and pressure. U.S. Pat. No. 6,217,851 describes preparing arginine bicarbonate from arginine hydroxide by bubbling carbon dioxide or by adding dry ice in excess into a solution of arginine free base. However, the efficiency of the existing process needs to be improved. The existing process is slow, requiring 24 to 48 hours to complete the reaction. Carbon dioxide has very limited solubility in water, and releasing the gas into the solution produces a maximum concentration of 1.2×10−5M at room temperature and its natural partial pressure (3.5×10−4 atmosphere). The solubility of arginine in water is only 15% weight/weight at room temperature. Producing a concentrated arginine bicarbonate solution (e.g., 40%) requires the continual addition of arginine to the solution, thereby increasing production time and requiring constant monitoring of the reaction. Thus, there is a need to improve methods to manufacture arginine bicarbonate.